Table 1

Histological and histometric findings in patients with chronic fatigue syndrome

AuthorsNo of patients biopsied/studiedHistologyHistometryOther findings and comments
Behan et al(1985)11 20/5015/20 scattered necrotic fibresModerate type 2 fibre predominance and hypertrophy in allConspicuous increase in peripheral mitochondria and occasional tubular inclusions. 30/40 abnormal jitter on SFEMG, 6/6 abnormal magnetic resonance spectroscopy of muscle
Byrne et al(1985)12 2/2NormalType 2 atrophy in both consistent with disuseMild reduction in state 3 respiration on polarography of isolated mitochondria
Byrne and Trounce (1987)13 11/11Minicore change in one case10/11 normal or mild 2b fibre atrophyGlycolytic and mitochondrial enzymes normal in vitro
Karpati et al(1990)14 ?Slight excess of central myonuclei, scattered small fibres in most. No inflammationStriking MHC class I expression in 2 cases
Behan et al(1991)15 50/503 cases occasional necrotic fibres. 2 cases tiny inflammatory foci. 4 cases regenerative changes. 25 cases prominent mitochondria on Gomori stain39/50 mild and focal (6 cases) to severe and diffuse (33 cases) type 2 atrophy. 4 cases type 1 atrophy40/50 (80%) cases showed structural mitochondrial abnormalities
Grau et al(1992)16 20/209/20 non-specific abnormalities, including scattered small or necrotic fibres, abnormal oxidative enzyme staining, focal myofibrillar loss3/20 type 2 hypertrophy0/20 MHC class I expression
Preedy et al(1993)17 23/232 cases had occasional split fibres, 2 others centronuclear chains3/20 type 2 atrophy, 5 others hypertrophy of one or both fibre typesSignificant reduction in muscle RNA/DNA composition (15%) but not muscle protein/DNA ratio
Edwards et al(1993)18 74/74Non-specific abnormalities in 81% of cases27% low prevalence, 12% high prevalence of type 1 fibres, 5/74 fibre atrophy or hypertrophySimilar abnormalities in 1/3 of normal control biopsies, TA studied in most cases
Connolly et al (1993)10 26/35Non-specific abnormalities in 9/10 cases with prominent myalgia cf. 3/16 other CFS casesAbnormal biopsy findings in CFS cases with prominent myalgia associated with increased fibre density on SFEMG, EDC biopsied in all cases
  • SFEMG=Single fibre electromyography, TA=tibialis anterior, EDC=extensor digitorum communis.